1. Field of the Invention
This invention relates to cosmetics for use in skin protection, more particularly to a skin-protecting cosmetic composition containing a hydroxypropyl-etherified glycolipid ester (hereinafter abbreviated as "POSL") represented by the formula (I), ##STR3## wherein R.sup.1 represents a methyl group or a hydrogen atom; R.sup.2 represents a saturated or unsaturated hydrocarbon group having carbon atoms of 11 to 15 when R.sup.1 is a methyl group, or a saturated or unsaturated hydrocarbon group having carbon atoms of 12 to 16 when R.sup.1 is a hydrogen atom; A represents the group ##STR4## R.sup.3 represents a saturated or unsaturated hydrocarbon group having carbon atoms of 1 to 20 or --(A).sub.h H; and a, b, c, d, e, f, g and h are eachintegers, whose sum ranges from 1 to 60.
2. Description of the Prior Art
Skin-protecting cosmetics have been used to prevent the skin from chapping and keep the same fresh-looking. For this purpose, there have been proposed hand creams, cold creams, vanishing creams, milky lotions, beauty washes and the like. These skin-protecting cosmetics are, in general, in the form of an emulsion or solution by emulsification or solubilization of various oil substances with surface active agents. Such oil substances include, for instance, hydrocarbons such as liquid paraffin, vaseline, paraffin wax, squalane, ceresine wax and the like; esters such as bees wax, spermaceti, carnauba wax, lanolin and synthetic esters of higher alcohols and fatty acids; alcohols such as long-chain aliphatic alcohols, lanolin alcohol and the like; and fatty acids.
The skin-protecting cosmetics are intended primarily to function such that the oil membrane formed on the skin after the evaporation of the moisture from inside of the skin acts as a barrier against the stimuli from outside and prevents the moisture in the skin from drying and hence protects the skin. However, the oil substance often causes damage to the skin because the oil itself is degenerated, for example, by oxidation when the oil membrane remains on the skin over a long period of time.
Therefore, the oil substance should possess a barrier ability against the stimuli from outside, that is, a blocking property, and at the same time, should be removed easily by washing. The usual oil substances known in the art have an excellent barrier ability but are liable to remain deposited on the skin even after washing, thereby resulting in damaged skin.
The present inventors have examined a wide variety of oil substances capable of protecting the skin and being easily removed by washing. As a result, they have found that POSL of the formula (I) achieves the above desired properties and that the oil substances present in the known skin-protecting cosmetics may be wholly or partially replaced by POSL.
Based on this finding, the present invention has been accomplished.